re PR tree-optimization/32100 (vrp bitfield miscompilation)

2007-05-28  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR tree-opt/32100
        * fold-const.c (tree_expr_nonnegative_warnv_p): Don't
        return true when truth_value_p is true and the type
        is of signed:1.

2007-05-28  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR tree-opt/32100
         * gcc.c-torture/execute/vrp-7.c: New test.

From-SVN: r125139

gcc/ChangeLog

+2007-05-28  Andrew Pinski  <andrew_pinski@playstation.sony.com>
+
+	PR tree-opt/32100
+	* fold-const.c (tree_expr_nonnegative_warnv_p): Don't
+	return true when truth_value_p is true and the type
+	is of signed:1.
+
 2007-05-28  Gerald Pfeifer  <gerald@pfeifer.com>
 
 	* doc/install.texi (Prerequisites): We no longer require Autoconf

gcc/fold-const.c

@@ -13485,9 +13485,14 @@ tree_expr_nonnegative_warnv_p (tree t, bool *strict_overflow_p)
       /* ... fall through ...  */
 
     default:
-      if (truth_value_p (TREE_CODE (t)))
-	/* Truth values evaluate to 0 or 1, which is nonnegative.  */
-	return true;
+      {
+	tree type = TREE_TYPE (t);
+	if ((TYPE_PRECISION (type) != 1 || TYPE_UNSIGNED (type))
+	    && truth_value_p (TREE_CODE (t)))
+	  /* Truth values evaluate to 0 or 1, which is nonnegative unless we
+             have a signed:1 type (where the value is -1 and 0).  */
+	  return true;
+      }
     }
 
   /* We don't know sign of `t', so be conservative and return false.  */

gcc/testsuite/ChangeLog

+2007-05-28  Andrew Pinski  <andrew_pinski@playstation.sony.com>
+
+	PR tree-opt/32100
+	* gcc.c-torture/execute/vrp-7.c: New test.
+	 
 2007-05-28  Brooks Moses  <brooks.moses@codesourcery.com>
 
 	* gfortran.dg/transfer_simplify_4.f90: New test.

gcc/testsuite/gcc.c-torture/execute/vrp-7.c

+
+void abort (void);
+
+struct T
+{
+  int b : 1;
+} t;
+
+void __attribute__((noinline)) foo (int f)
+{
+  t.b = (f & 0x10) ? 1 : 0;
+}
+
+int main (void)
+{
+  foo (0x10);
+  if (!t.b)
+    abort ();
+  return 0;
+}